Motor for washing machine and washing machine having the same

ABSTRACT

A washing machine includes a tub; a drum arranged in the tub; and a motor mounted on the rear wall, the motor including a stator and a rotor. The stator includes a stator core, a first insulator and a second insulator. The rotor includes a rotor frame including a bottom, air inlets formed at the bottom, and a side wall extended from the bottom. The first insulator is disposed between the stator core and the bottom of the rotor frame, the first insulator including at least one heat dissipation hole. The second insulator is disposed between the stator core and the rear wall of the tub, the second insulator including at least one guide member to position the second insulator on the rear wall of the tub. The guide member is exposed through the dissipation hole when the stator is coupled to the rear wall of the tub.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/064,691 filed Apr. 8, 2011, which claims the benefit of Korean PatentApplication No. 10-2010-0032716, filed on Apr. 9, 2010 in the KoreanIntellectual Property Office, the disclosures of which are incorporatedherein by reference.

BACKGROUND

1. Field

Embodiments relate to a motor to drive a drum of a washing machine.

2. Description of the Related Art

In general, a washing machine is an apparatus serving to wash laundryusing electric power, and includes a tub to store washing water, a drumrotatably installed in the tub, and a motor to rotate the drum.

When the drum is rotated by the motor under the condition that laundryand washing water containing a detergent are placed in the drum,contaminants are removed from the laundry through friction of thelaundry with the drum and the washing water containing the detergent.

Washing machines are divided into an indirect drive type in whichdriving force of a motor is transmitted to a drum through a powertransmission unit, such as a belt and a pulley, and a direct drive typein which driving force of a motor is directly transmitted to a shaft ofa drum.

A motor of a direct drive type washing machine includes a stator mountedon a tub, and a rotor arranged around the stator and electromagneticallyinteracting with the stator.

SUMMARY

Therefore, it is an aspect to provide a motor for washing machines inwhich a heat dissipation structure is improved, and a washing machinehaving the same.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the invention.

In accordance with one aspect, in a motor for washing machines with astator mounted on a tub of a washing machine, the stator includes astator core including a base and teeth arranged along the outercircumferential surface of the base and separated from each other, afirst insulator arranged on the lower surface of the stator core, andincluding a core receiving unit to receive the stator core, and amounting unit extended from the core receiving unit inwardly in theradial direction of the stator to mount the stator on the tub andprovided with at least one heat dissipation hole, and a second insulatorarranged on the upper surface of the stator core, and including a coverto cover the base and teeth receiving parts corresponding to the teeth.

An inner diameter of the cover may be greater than an inner diameter ofthe mounting unit.

A length of the cover protruded inwardly in the radial direction of thestator may be smaller than a length of the mounting unit protrudedinwardly in the radial direction of the stator.

The mounting unit may include a plurality of connection bosses arrangedin the circumferential direction of the mounting unit and separated fromeach other, and the plurality of connection bosses may be extended up tothe tub and supported by the tub when the stator is mounted on the tub.

The at least one heat dissipation hole may be arranged between theplurality of connection bosses.

The mounting unit may further include at least one reinforcing ribformed in the circumferential direction of the stator.

The core receiving unit may include a support rib to support the innersurface of the base, and the mounting unit may further include radialreinforcing ribs to connect the support rib and the plurality ofconnection bosses.

The mounting unit may further include connection ribs to connect thesupport rib and the at least one reinforcing rib formed in thecircumferential direction of the stator.

The mounting unit may further include a plurality of positioning bossesarranged at positions adjacent to the plurality of connection bosses soas to be connected with the second insulator, and connection partsconnected with the plurality of positioning bosses may be provided onthe cover.

The tub may be provided with a plurality of guide protrusions protrudedfrom a rear wall of the tub, and a plurality of guide holes to receivethe plurality of guide protrusions may be provided on the cover.

The guide holes may be exposed to the outside through the at least oneheat dissipation hole, if the first insulator and the second insulatorare connected to each other.

The at least one heat dissipation hole may be arranged between theplurality of connection bosses, and be provided by cutting off spacesformed by the at least one reinforcing rib and the connection ribs.

In accordance with another aspect, in a washing machine which has a tubprovided with a rear wall, a drum arranged in the tub, and a motormounted on the rear wall of the tub to drive the drum and including astator core and a first insulator and a second insulator arranged on thelower and upper surfaces of the stator core to surround the stator core,the first insulator includes a mounting unit including a plurality ofconnection bosses arranged in the circumferential direction of the firstinsulator and separated from each other so as to connect the firstinsulator to the tub, and a circular reinforcing rib to connect asupport rib supporting a part of the inner surface of the stator coreand the plurality of connection bosses, wherein at least one heatdissipation hole to dissipate heat of the stator core is provided on themounting unit.

The stator core may include a ring-shaped base and teeth arranged alongthe outer circumferential surface of the base and separated from eachother, and the second insulator may include a ring-shaped cover to coverthe base and an inner diameter of the cover may be greater than an innerdiameter of the reinforcing rib.

The tub may be provided with a plurality of guide protrusions protrudedfrom the rear wall of the tub, the cover may be provided with aplurality of prominent parts protruded inwardly in the radial directionof the second insulator, and guide holes corresponding to the pluralityof guide protrusions may be provided on the plurality of prominentparts.

The guide holes may be arranged at positions to be exposed to theoutside through the at least one heat dissipation hole, if the firstinsulator and the second insulator are connected to each other.

The mounting unit may further include a plurality of positioning bossesarranged at positions adjacent to the plurality of connection bosses soas to be connected with the second insulator, and a circular reinforcingrib to connect the plurality of positioning bosses to each other.

The mounting unit may further include connection ribs to connect thesupport rib and the circular reinforcing rib connecting the plurality ofconnection bosses to each other and the circular reinforcing ribconnecting the plurality of positioning bosses to each other, and the atleast one heat dissipation hole may be arranged between the plurality ofconnection bosses and be provided by cutting off spaces formed by thecircular reinforcing ribs and the connection ribs.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings of which:

FIG. 1 is a washing machine in accordance with one embodiment;

FIG. 2 is an exploded perspective view of a motor in accordance with theembodiment;

FIG. 3 is an exploded perspective view of a stator of the motor of FIG.2;

FIG. 4 is a view illustrating a first insulator of the stator of FIG. 3;

FIG. 5 is a top plan view of the stator of the motor of FIG. 2; and

FIG. 6 is a bottom plan view of the stator of the motor of FIG. 2.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments, examples ofwhich are illustrated in the accompanying drawings, wherein likereference numerals refer to like elements throughout.

FIG. 1 is a washing machine in accordance with one embodiment.

As shown in FIG. 1, a washing machine 1 in accordance with thisembodiment includes a cabinet 10 forming an external appearance of thewashing machine 1, a tub 20 arranged within the cabinet 10, a drum 30rotatably arranged within the tub 20, and a motor 40 to drive the drum30.

An inlet 11 through which laundry is put into the drum 30 is formedthrough the front surface of the cabinet 10, and the inlet 11 is openedand closed by a door 12 installed on the front surface of the cabinet10.

A water supply pipe 50 to supply washing water to the tub 20 isinstalled above the tub 20.

One end of the water supply pipe 50 is connected to an external watersupply source (not shown), and the other end of the water supply pipe 50is connected to a detergent supply device 60.

The detergent supply device 60 is connected to the tub 20 through aconnection pipe 55. Water supplied through the water supply pipe 50 issupplied to the inside of the tub 20 together with a detergent by way ofthe detergent supply device 60.

A drain pump 70 and a drain pipe 75 to discharge water in the tub 20 tothe outside of the cabinet 10 are installed under the tub 20.

A plurality of through holes 31 to circulate washing water is formedthrough the circumferential surface of the drum 30, and a plurality oflifters 32 to raise and drop the laundry during rotation of the drum 30is installed on the inner circumferential surface of the drum 30.

A driving shaft 80 is arranged between the drum 30 and the motor 40. Thedriving shaft 80 transmits rotary force of the motor 40 to the drum 30.

One end of the driving shaft 80 is connected to the drum 30, and theother end of the driving shaft 80 is extended to the outside of a rearwall 21 of the tub 20.

A bearing housing 82 rotatably supporting the driving shaft 80 isinstalled on the rear wall 21 of the tub 20.

The bearing housing 82 is made of aluminum alloy, and may be formedunder the condition that the bearing housing 82 is inserted into therear wall 21 of the tub 20 when the tub 20 is formed by injectionmolding.

Bearings 84 are installed between the bearing housing 82 and the drivingshaft 80 so as to efficiently rotate the driving shaft 80.

FIG. 2 is an exploded perspective view of the motor in accordance withthe embodiment of the present invention, FIG. 3 is an explodedperspective view of a stator of the motor of FIG. 2, and FIG. 4 is aview illustrating a first insulator of the stator of FIG. 3.

As shown in FIG. 2, the motor 40 includes a stator 100 mounted on therear wall 21 of the tub 20, and a rotor 200 arranged around the stator100 and rotated through electromagnetic interaction with the stator 100.

The rotor 200 includes a rotor frame 210, and an injection-moldedproduct 230 formed on the rotor frame 210 by injection molding.

The rotor frame 210 includes a bottom 211 and a side wall 212 protrudedfrom the edge of the bottom 211, and is arranged so as to surround thestator 100.

The rotor frame 210 is made of a magnetic material, and is formed with athickness of 1.6 mm or less in order to improve productivity and reducematerial costs.

Air inlets 216 through which external air is introduced into the rotorframe 210 during rotation of the rotor 200 are formed through the bottom211 of the rotor frame 210, and cooling blades 232 protruded to theinside of the rotor frame 210 are provided between the air inlets 216.

The side wall 212 of the rotor frame 210 includes a bending part 217bent in a direction of extending the radius of the rotor frame 210, andmagnets 250 are arranged on the inner surface of the side wall 212 abovethe bending part 217 in the circumferential direction of the rotor frame210.

The magnets 250 are opposite to coils 160 of the stator 100 by adesignated interval so as to electromagnetically interact with thestator 100.

Holes 218 are arranged on the bending part 217 of the side wall 212 inthe circumferential direction of the rotor frame 210. A workerassembling the motor 40 with the tub 20 easily observes whether or not aproper interval between the stator 100 and the magnets 250 is uniformlymaintained through the holes 218 formed through the bending part 217.

A back yoke ring 270 is connected with the outer surface of the sidewall 212 of the rotor frame 210. The back yoke ring 270 serves toreinforce the side wall 212 of the rotor frame 210 as well as to preventleakage of a magnet field of the magnets 250 and thus to improve theperformance of the motor 40.

The back yoke ring 270 includes a plurality of unit yokes 272 arrangedin the circumferential direction of the rotor frame 210. Each of theunit yokes 272 includes a connection protrusion 274 formed at one endthereof, and a connection hole 276 formed at the other end thereof.

The connection protrusion 274 includes inclined planes 275 so as to havea sectional area gradually increasing in the protruded directionthereof, and the connection hole 276 has a shape corresponding to theconnection protrusion 274.

The connection protrusion 274 of one unit yoke 272 is connected to theconnection hole 276 of a neighboring unit yoke 272. The unit yokes 272are arranged in a ring shape, and are fixed to the outer surface of theside wall 212 through press fitting.

When the back yoke ring 270 is fixed to the side wall 212 through pressfitting, the unit yokes 272 are slightly distant from each other so thatthe radius of the back yoke ring 270 is extended, and thus press fittingof the back yoke ring 270 to the side wall 212 is smoothly achieved.

Further, while the radius of the back yoke ring 270 is extended, theconnection protrusions 274 of the unit yokes 272 are strongly engagedwith the connection holes 276 of the unit yokes 272, and thus the backyoke ring 270 is firmly fixed to the side wall 212.

The injection-molded product 230 is formed on the bottom 211 of therotor frame 210 by injection molding, and is integrated with the rotorframe 210.

A serration member 240 made of a metal, such as iron or aluminum alloy,is inserted into the center of the injection-molded product 230. Theserration member 240 is connected with the end of the driving shaft 80extended to the outside of the tub 20.

As shown in FIG. 3, the stator 100 includes a stator core 110, a firstinsulator 120 and a second insulator 150 respectively arranged on thelower and upper surfaces of the stator core 110 so as to surround thestator core 110, and the coils 160 (with reference to FIG. 2).

The stator core 110 includes a ring-shaped base 112, and teeth 114arranged along the outer circumferential surface of the base 112 andprotruded outwardly in the radial direction of the stator 100.

The stator core 110 may be obtained by forming unit cores by stackingiron panels, obtained by press processing, and then by connecting theunit cores in the circumferential direction.

Further, the stator core 110 may be obtained by rolling a band-shapediron panel having the base 112 and the teeth 114 in a spiral shape.

Insertion holes 116 are arranged on the base 112 of the stator core 110in the circumferential direction. Fastening members, such as pins orrivets, are inserted into the insertion holes 116, thereby connectingrespective layers constituting the stator core 110.

The first insulator 120 and the second insulator 150 are made of anelectrically insulating material, and are arranged on the lower andupper surfaces of the stator core 110 so as to cover the stator core110.

When the stator 100 is mounted on the tub 20, the second insulator 150is arranged adjacent to the rear wall 21 of the tub 20, and the firstinsulator 120 is arranged on one side of the stator core 110 opposite tothe second insulator 150.

The first insulator 120 includes a core receiving unit 121 to receivethe stator core 112, and a ring-shaped mounting unit 130 extended fromthe outer surface of the core receiving unit 121 inwardly in the radialdirection of the first insulator 120 to mount the stator 110 on the tub20.

The core receiving unit 121 includes a ring-shaped base receiving part121 a corresponding to the base 112 of the stator core 110, and firstteeth receiving parts 121 b corresponding to the teeth 114 of the statorcore 110.

The second insulator 150 includes a ring-shaped cover 153 arranged onthe upper surface of the base 112 of the stator core 110, and secondteeth receiving parts 151 corresponding to the teeth 114 of the statorcore 110.

When the first insulator 120 and the second insulator 150 are connectedto each other, the stator core 110 is received in a space formed by thebase receiving part 121 a, the first teeth receiving parts 121 b, thesecond teeth receiving parts 151, and the cover 153.

The first insulator 120 and the second insulator 150 are provided withfirst coil support parts 122 and second coil support parts 152.

Each first coil support part 122 and each second coil support part 152forms one coil support unit, when the first insulator 120 and the secondinsulator 150 are connected to each other, and the coils 160 (withreference to FIG. 2) are wound on the respective coil support units.

An inner diameter D1 of the mounting unit 130 is smaller than an innerdiameter D2 of the cover 153 so as to expose the mounting unit 130 ofthe first insulator 120 from the cover 153 of the second insulator 150when the first insulator 120 and the second insulator 150 are connectedto each other.

With reference to FIGS. 3 and 4, the mounting unit 130 is formed by asupport rib 131 supporting one side wall of the base receiving part 121a to support the inner wall of the stator core 110 received in the corereceiving unit 121, and circular reinforcing ribs 132 and 133 separatedfrom the support rib 131 by designated intervals and formed in thecircumferential surface of the first insulator 120.

A plurality of connection bosses 135 is provided on the mounting unit130, the inner diameter D1 of which is smaller than the inner diameterD2 of the cover 153. Each connection boss 135 is provided with aconnection hole 135 a, into which a fastening member 104, such as abolt, is inserted.

The connection bosses 135 are arranged so as to be separated from eachother in the circumferential direction of the mounting unit 130. Eachconnection boss 135 is made of one member extended up to the rear wall21 of the tub 20 in the axial direction of the motor 40 so that one end135 b of each connection boss 135 is supported by the rear wall 21 ofthe tub 20 when the stator 100 is fixed to the tub 20 by the fasteningmembers 140.

A sleeve 139 is inserted into the connection hole 135 a of eachconnection boss 135. The sleeves 139 are made of a metal. The sleeves139 reinforce the connection bosses 135, thereby preventing damage tothe connection bosses 135 due to the insertion process of the fasteningmembers 104 or vibration transmitted from the tub 20 during theoperation of the washing machine.

Further, the connection bosses 135 are connected to each other by thecircular reinforcing rib 132 connecting the outer surfaces of theconnection bosses 135, and the connection bosses 135 and the support rib131 are connected to each other by radial reinforcing ribs 134.

Such reinforcing ribs 132 and 134 serve to maintain rigidity of theconnection bosses 135 relative to fastening force and simultaneously toprevent changes in relative positions of the connection bosses 135.

Further, a plurality of positioning bosses 138 separated from each otherin the circumferential direction of the mounting unit 130 is provided onthe mounting unit 130, and each positioning boss 138 is provided with apositioning hole 138 a formed therein.

The positioning bosses 138 are arranged adjacent to the connectionbosses 135.

The positioning bosses 138 are extended in the axial direction of themotor 40, and are formed with a height lower than the connection bosses135. Thereby, there is a height difference between the upper surfaces ofthe positioning bosses 138 and the upper surfaces of the connectionbosses 135.

Further, the circular reinforcing rib 133 connecting the positioningbosses 138 to each other to reinforce the rigidity of the positioningbosses 138 is provided on the mounting unit 130.

The reinforcing rib 133 has a trajectory passing through the centers ofthe respective positioning bosses 138, thereby connecting the respectivepositioning bosses 138 to each other.

Further, connection ribs 136 connecting the support rib 131 and thereinforcing ribs 132 and 133 to each other are provided on the mountingunit 130.

The support rib 131 and the reinforcing ribs 132 and 133 are connectedby the connection ribs 136 extended radially, thereby effectivelypreventing bending or warping of the first insulator 120.

Heat dissipation holes 137 to dissipate heat from the stator core 110are provided on the mounting unit 130.

The heat dissipation holes 137 to dissipate heat from the stator core110 function as air circulation passages through which external air isintroduced into the base 112 of the stator core 110 received in the basereceiving part 121 a, thereby improving a cooling effect of the statorcore 110.

The heat dissipation holes 137 are vertically formed through themounting unit 130 between the plural connection bosses 135 separatedfrom each other in the circumferential direction of the mounting unit130. The heat dissipation holes 137 may be formed by cutting off spacesformed by the circular reinforcing ribs 132 and 133 and the connectionribs 136.

With reference to FIG. 2, the second insulator 150 includes thering-shaped cover 153, the inner diameter D2 of which is larger than theinner diameter D1 of the mounting unit 130 of the first insulator 120,and the cover 153 is configured to cover the base receiving part 121 aof the first insulator 120, the reinforcing rib 133, and the reinforcingribs 133 connecting the positioning bosses 138 to each other.

A plurality of connection parts 154 protruded inwardly in the radialdirection of the second insulator 150 to achieve assembly with the firstinsulator 120 is provided on an inner diameter part 153 a of the cover153.

The connection parts 154 are provided at positions corresponding to thepositioning bosses 138 of the first insulator 120 when the firstinsulator 120 and the second insulator 150 are connected to each other.

Protrusions 154 a extended downwardly in the axial direction of themotor 40 and inserted into the positioning holes 138 a of thepositioning bosses 138 are provided on the connection parts 154.

Thereby, when the first insulator 120 and the second insulator 150 areconnected to each other, the protrusions 154 a provided on theconnection parts 154 of the second insulator 150 are inserted into thepositioning holes 138 a of the first insulator 120, thereby easilyachieving assembly of the first insulator 120 and the second insulator150.

Further, a plurality of prominent parts 155 protruded inwardly in theradial direction of the second insulator 150 to guide an assemblyposition of the stator 100 when the stator 100 is mounted on the tub 20is provided on the inner diameter part 153 a of the cover 153, and aguide hole 156 is provided on each prominent part 155.

The prominent parts 155 are arranged so that the tips of the respectiveprominent parts 155 contact the upper end of the reinforcing rib 132forming the inner diameter D1 of the mounting unit 130 of the firstinsulator 120, as shown in FIG. 5, when the first insulator 120 and thesecond insulator 150 are connected to each other.

The guide holes 156 are arranged at positions exposed to the heatdissipation holes 137 so as to be recognized from the outside throughthe heat dissipation holes 137 formed through the mounting unit 130 ofthe first insulator 120, as shown in FIG. 6, when the first insulator120 and the second insulator 150 are connected to each other.

Further, the guide holes 156 are arranged at positions corresponding toguide protrusions 22 provided on the rear wall 21 of the tub 20 so thatthe stator 100 is mounted at a correct position, as shown in FIG. 1.

Thereby, if the stator 100 is mounted on the tub 20, the positions ofthe guide holes 156 provided on the prominent parts 155 of the secondinsulator 150 are easily recognized through the heat dissipation holes137 of the first insulator 120, and thus the guide protrusions 22provided on the tub 20 are easily inserted into the guide holes 156,thereby facilitating fixation of the stator 100 to the tub 20.

Further, a power connection part 157 is provided on the second insulator150 so as to supply power to the coils 160 of the stator 100.

As is apparent from the above description, a motor for washing machinesin accordance with one embodiment improves cooling efficiency of astator core.

Further, the motor for washing machines in accordance with theembodiment facilitates assembly of a stator with a tub as connectionportions between the stator and the tub may be easily seen from theoutside when the stator is fixed to the tub.

Although a few embodiments have been shown and described, it would beappreciated by those skilled in the art that changes may be made inthese embodiments without departing from the principles and spirit ofthe invention, the scope of which is defined in the claims and theirequivalents.

What is claimed is:
 1. A washing machine comprising: a tub provided witha rear wall; a drum arranged in the tub; and a motor mounted on the rearwall of the tub to drive the drum, the motor including a stator and arotor, wherein the stator comprises a stator core, a first insulator anda second insulator disposed on an opposite side of the first insulatorso as to cover the stator core, wherein the rotor comprises a rotorframe including a bottom, air inlets formed at the bottom, and a sidewall extended from the bottom, wherein the first insulator comprises aplurality of heat dissipation holes arranged in a circumferentialdirection of the first insulator to dissipate heat of the stator core,wherein the second insulator is disposed between the stator core and therear wall of the tub, the second insulator including a plurality ofguide holes arranged in a circumferential direction of the secondinsulator to be coupled to a plurality of guide protrusions protrudedfrom the rear wall of the tub, and wherein each of the guide holes isexposed through one of the plurality of heat dissipation holes while thefirst insulator and the second insulator are coupled to each other. 2.The washing machine according to claim 1, wherein: the stator coreincludes a base and teeth arranged along the outer circumferentialsurface of the base and separated from each other; the first insulatorincludes a core receiving unit to receive the stator core, and amounting unit extended from the core receiving unit inwardly in a radialdirection of the stator to mount the stator on the tub and provided withthe plurality of heat dissipation holes; and the second insulatorincludes a cover to cover the base and teeth receiving partscorresponding to the teeth.
 3. The washing machine according to claim 2,wherein an inner diameter of the cover is greater than an inner diameterof the mounting unit.
 4. The washing machine according to claim 2,wherein a length of the cover protruded inwardly in the radial directionof the stator is smaller than a length of the mounting unit protrudedinwardly in the radial direction of the stator.
 5. The washing machineaccording to claims 2, wherein the mounting unit includes a plurality ofconnection bosses arranged in a circumferential direction of themounting unit and separated from each other, and the plurality ofconnection bosses is extended up to the tub and supported by the tubwhen the stator is mounted on the tub.
 6. The washing machine accordingto claim 5, wherein the heat dissipation holes are arranged between theplurality of connection bosses.
 7. The washing machine according toclaim 5, wherein the mounting unit further includes at least onereinforcing rib formed in a circumferential direction of the stator. 8.The motor for washing machines according to claim 7, wherein: the corereceiving unit includes a support rib to support the inner surface ofthe base; and the mounting unit further includes radial reinforcing ribsto connect the support rib and the plurality of connection bosses. 9.The washing machine according to claim 8, wherein the mounting unitfurther includes connection ribs to connect the support rib and the atleast one reinforcing rib formed in the circumferential direction of thestator.
 10. The washing machine according to claim 5, wherein: themounting unit further includes a plurality of positioning bossesarranged at positions adjacent to the plurality of connection bosses soas to be connected with the second insulator; and connection partsconnected with the plurality of positioning bosses are provided on thecover.
 11. The washing machine according to claim 9, wherein the heatdissipation holes are arranged between the plurality of connectionbosses, and are provided by cutting off spaces formed by the at leastone reinforcing rib and the connection ribs.